Introduction

• Cells are fundamental to the human body.
• Less-advanced life forms like amoebas consist of a single cell.
• The human body comprises billions of specialized cells.
• Protoplasm is a viscous liquid matrix supporting internal cellular structures.
• Each cell is essentially a tiny mass of colorless protoplasm.
• Protoplasm facilitates intracellular transport of nutrients, signaling molecules, ATP, and proteins.
• Tissues consist of cells with a shared function growing closely together.
• Organs are groups of tissues performing interrelated tasks.
• Homeostasis is maintaining a stable internal environment.
• Disruptions to homeostasis can significantly impact the organism.

Cell Structure

• Two major cell classes exist: sex cells (germ or reproductive cells) and somatic cells.
• Sex cells include sperm in males and oocytes (eggs) in females.
• Somatic cells encompass all other body cells.
• Three basic cell parts include the cell membrane, nucleus, and cytoplasm.
• Organelles are specialized microscopic structures performing specific functions within the cell.

Cell Membrane

• It controls the movement of substances in and out of the cell.
• The extracellular space is outside the cell.
• The intracellular space is inside the cell.
• It facilitates selective communication between intracellular and extracellular environments, enabling cellular movement.
• It gives the cell shape.
• It is required for biologic activities.
• It detects and transmits signals from outside the cell.
• It allows cells to adhere to one another to form tissues.
• It is semipermeable, allowing certain substances to pass through while restricting others.
• Selective permeability allows only certain substances to enter or exit.
• Primarily composed of lipids and proteins, usually arranged in a double layer of phospholipid molecules.
• The phosphate portion constitutes the outer surface, and the fatty acid portion constitutes the inner surface — the bilayer.
• Proteins embedded in the lipid bilayer serve as transporters, signal receptors, channels, and ion channels.

Permeability

• A selectively permeable membrane permits some, but not all, substances to pass through.
• It also helps to maintain homeostasis.
• Electrolytes are chemicals made of salt or acid substances dissolved in the blood.
• Electrolytes act as ionic conductors in a solvent like water.

Transport Through the Cell Membrane

• Several mechanisms facilitate the movement of materials across the cell membrane.
• These mechanisms include: diffusion, osmosis, facilitated diffusion, active transport, endocytosis, and exocytosis.

Diffusion

• Movement of particles or solutes from a high to a low concentration area takes place
• The degree of diffusion depends on the membrane's permeability and the concentration gradient.
• Small molecules diffuse more easily than large ones.
• Watery solutions diffuse more rapidly than thicker ones.

Osmosis

• Osmosis constitutes solvent movement from a low to a high solute concentration area across a selectively permeable membrane.
• Osmotic pressure measures water's tendency to move by osmosis across a membrane.
• Crenation is cell shrinkage from excessive water loss.
• Lysis is cell swelling and bursting due to excessive water intake.

Facilitated Diffusion

• A carrier molecule moves substances into or out of cells from high to low concentration areas.
• Facilitated diffusion does not require energy.
• The number of molecules transported is directly proportional to the concentration.

Active Transport

• It constitutes the movement of a substance against a concentration or gradient,
• This needing energy.
• The movement is opposite to diffusion.
• It may involve exchanging one substance for another.

Filtration

• Filtration involves water movement out of plasma, across the capillary membrane, into interstitial space.
• It is caused by hydrostatic pressure.
• Oncotic force draws water back into the capillary from the interstitial space.

Endocytosis

• It is the process of material uptake through the cell membrane
• It relies on a membrane-bound droplet or vesicle formed within the cell's protoplasm.
• Two types include phagocytosis, which involves solid particles ("cell eating"), and pinocytosis, involving liquids ("cell drinking").

Exocytosis

• It is the release of secretions from cells.
• Secretions accumulate within vesicles.
• Vesicles fuse with the membrane, and their contents are released.
• Examples include digestive enzymes secreted by the pancreas and mucus secretion by the salivary glands.

Nucleus

• The nucleus is the largest, most visible structure inside a cell, containing DNA.
• A cell without a nucleus disintegrates within 3–4 months.
• It houses the genetic instructions for protein synthesis, which determines cell structure and function.
• Round in shape, the nucleus is enclosed by a double nuclear envelope.
• The nuclear envelope consists of inner and outer lipid membranes.
• It possesses a protein lining that allows certain molecules to exit.
• Nucleoplasm is a fluid inside the nucleus that suspends the nucleolus, made mostly of RNA and protein, and chromatin.
• Chromatin composes of loosely coiled DNA and protein fibers that condense.

Cytoplasm

• The cytoplasm is the matrix substance containing all cellular contents between the cell membrane and the nucleus.
• It serves as the medium for chemical reactions.
• Cytoplasm makes up most of cell volume and suspends organelles.
• Organelles are internal structures carrying out necessary processes for the body’s function.
• Organelles include centrioles, cilia, and flagella.

Centrioles

• Centrioles are important in forming the spindle apparatus.
• Spindle fibers and microtubules radiate from the centrioles.
• They are essential in cell division.
• They form the structure needed for DNA strand movement.

Cilia

• Cilia consists of hair-like projections on the cell surface, capable of motion.
• These projections assist in moving materials.
• Mucus is transported from lower areas of the lungs to the throat by cilia present in the trachea and bronchi.

Flagellum

• A flagellum is a tail-like microtubule structure that propels sperm.
• Sperm use flagella to move through the vagina into the uterus.

Ribosomes

• Ribosomes are organelles containing RNA and protein.
• They interac with RNA to join amino acids and form proteins, which takes place in the endoplasmic reticulum.

Endoplasmic Reticulum

• Its a series of membranes in which specific proteins and fats are manufactured.

Golgi Apparatus

• Itconsists of membranes within the protoplasm.
• It aids the formation of various carbohydrate and complex protein molecules.

Lysosomes

• Lysosomes consist of membrane-bound vesicles with enzymes.
• They function as an intracellular digestive system.

Peroxisomes

• Similar in function to lysosomes and found in high concentrations in the liver, peroxisomes neutralize toxins like alcohol.

Genetic Material

• Genetic material in the nucleus:
• Deoxyribonucleic acid (DNA) found in chromosomes
• Ribonucleic acid (RNA) found in nucleoli.
• Nucleoli – spherical intranuclear structures

Cytosol

• The cytosol is the fluid within the cytoplasm.
• It contains water, glucose, amino acids,fatty acids, ions, lipids, proteins, ATP, and waste.
• The cytosol is the site of many chemical reactions.

Cell Division

• Remodeling describes the process of ongoing cell renewal.
• Cell division includes meiosis and mitosis.

Meiosis

• Meiosis is a specialized form of cell division for mature sperm and ovum.
• Normal cells have 46 chromosomes (diploid number), containing two sets of chromosomes.
• Sperm and ova have 23 chromosomes (haploid number).
• When sperm and ovum unite, the final organism contains 46 chromosomes.
• Meiosis involves two consecutive cell divisions, each with four stages, resulting in cells with a haploid chromosome number.

Mitosis

• Mitosis involves cytokinesis: cytoplasm division.
• All cells, except egg and sperm cells, can divide by mitosis and precision is essential.

Stages of Mitosis:

• Prophase: new centriole pairs move to opposite ends of the cell.
• Metaphase: During metaphase chromosomes align in the middle (equatorial plane) and attach to spindle fibers,
• Anaphase involves centromere sections moving apart to create individual chromosomes move toward cell ends.
• At telophase chromosomes have arrived at each pole, and new nuclear membranes form.

Types of Tissues

• Tissues refer to groups of similar cells working together.
• They are classified into four types: epithelial, connective, muscle, and nerve.

Epithelial Tissue

• It covers external surfaces of the body and lines internal organs.
• Most epithelial tissues have a basement membrane, which is a noncellular layer securing overlying tissues.
• They can be classified by the shape of each and the number of cell layers. Shapes include squamous, cuboidal, and columnar.
• Squamous epithelium are flat sheets.
• Cuboidal epithelium are rows of square-shaped cells.
• Columnar epithelium are rows of tall, thin cells.
• Simple epithelium consists of a single cell layer.
• Stratified epithelium comprises more than one cell layer.
• Pseudostratified epithelium features a single layer of varying cell heights.
• Transitional epithelium consists of stratified layers that change shape from cuboidal to squamous when stretched.

Connective Tissue

• Connective tissue binds other tissues together.
• It includes bone, cartilage, adipose tissue, and scar tissue.
• Connective tissues contain many types of cells and extracellular fibres distributed in a syrup-like ground substance.
• Types can be tissue proper, supportive, and fluid
• It Includes those connective tissues with many types of cells and extracellular fibres in a syrup-like ground substance. -Dense connective tissue – contains many collagenous fibers and appears white.
• Loose connective tissue -Adipose tissue
• Areolar tissue
• Reticular Tissue
• Less diverse cell population and a matrix that has many more densely packaged fibers than connective tissue proper
• Protects soft tissues and carries most of or all of the body’s weight
• Cartilage
• Supports, frames, and attaches to many underlying tissues and bones
• Blood
• Contains formed elements suspended in blood plasma
• Lymph -Forms as interstitial fluid enters the lymphatic vessels .

Muscle Tissue

• It overlies the skeleton’s framework.
• It can be classified by structure (striated or nonstriated) and function (voluntary or involuntary).
• Striated muscle has microscopic bands.
• Nonstriated (smooth) muscle lacks striations.
• Voluntary muscles are consciously controlled.
• Involuntary muscles aren’t normally under conscious control.
• Main types of muscle tissue are skeletal, cardiac, and smooth.
• Skeletal muscle is striated voluntary muscle.
• Cardiac muscle is striated involuntary muscle, which constitutes the myocardium.
• Smooth muscle is nonstriated involuntary muscle.
• It composes hollow internal organ walls.

Nervous Tissues

• Specialized for electrical impulse conduction include:
• Neurons: main conducting cells.
• Neuroglia: (glial cells) support cells.
• The brain, spinal cord, and peripheral nerves are nervous tissues.
• Dendrites receive electrical impulses from axons of other nerve cells and conduct them toward the cell body.
• Axons conduct electrical impulses away.
• Neurons generally have one axon but possibly several dendrites.

Organs

• Organs are various tissues working together to perform tasks.
• These tissues components can pump blood through arteries and veins.
• The skin (integument) contains all four tissue types and serves as the body's largest organ.

Organ Systems

• Organ systems refer to groups of organs that share a common function.
• They include the skeleton and muscles, the circulatory system, the respiratory system, and the nervous system.
• Organ systems unite to form a complete organism.
• Organism: any individual living thing
• The human organism is complex, consisting of mutually dependent organs and organ systems.

Body Regions

• Two major body regions are Appendicular and axial
• Appendicular: includes the extremities and their girdles. -Girdles: bony structure that attach limbs to body. Upper extremity (arm, forearm wrist, hand), attaches to body at shoulder
  • axilla-arm pit Antecubital: bend in elbow
• Lower extremity: thigh, leg, ankle and foot and attached to the body by hip.
• Popliteal fossa: space behind knee
• Axial area: head neck and trunk the scalp is the skin layer on the head. There are five layers, which include skin, subcutaneous tissues, muscles, loose connective tissues and periosteum.

Axial Region – Meninges & Head

• The meningies are the membrane in the skull covering the brain: dura mater, arachnoid and pia mater.
• The periosteum is a membrane that covers the outside of the skull and all the bones.
• The skull houses the brain.
• It consists of the cranium and facial bones linked at sutures (connected together at special points known as sutures) including fontanelles, which soften during childbirth.

Axial Region - Neck and Trunk

• There are three triangles, the anterior, cartoid, and posterior.
• Trunk subdivided into the thorax, abdomen, and pelvis.

Body Cavities

• Body cavities are hollow areas in the body containing organs/organ systems.
• Cranial cavity: hollow portion of skull housing the brain (connected and is continous with the spinal cavity)
• Spinal cavity runs throught the vertebrae in the spine.
• The muscular diaphragm divides the trunk into the thoracic and abdominal cavities.
• Tissue membranes of the body
  • Serous membrane -a specialized form of thick connective tissue that lines the cavity of the trunk.
  • Pariatal portion - lines walls of cavity
• Visceral Portion- covers the internal organs
• Function – They secret fluid that fill pace between viceral and parital regions and protect from friction.

Thoracic Cavity

• It is found between the base of neck to diaphragm formed roughly by the circular area of the rib cage
• There are major organs w/i thoracis cavity that are related to cardiovascular and reparatory (heart/Lungs). Lungs covered by pleura, serous membrane, and pluaral space, that contains fluids.
• The mediastinum is a space between lungs the has many structure, trachea. Mainstream of blood vessels, heart etc.
• The heart is protected by the pericarduim -There are also serous membrain witn this part of the body. Like pleural space there space, the pericardial space rarely contains large amount of fluids.

Abdominal Cavity

• A single cavity the exdne form pelvic bone/ diaphram and linned w/ serous membrances called peritinum.
• Miscentary: membrouse double fold tissue on abdmon and various organ.
• The abduction has a quadrant.
• A umbilicus is used. I
• is a point a whcihthe abdomen gets divided it the quadrants .
• Rectoreperitoneum Space: - area posterior that parietal peritonium, Kidner. Pacreas, cadunem major blood vessel and and here, these structures are known as Retroperitoneal Organ.

Pelvic Cavity.

• The lwoer postion of dabdmoinal. The llium, ishiumis, pubic sacrum, crocyx
  • Provides internal organ protections
• Has - gastrointetinal, reproductive and urinary system,

Cellular Injury

• May happen with hypoxia, schemia,chemical, inject, mmonglic injuyr, physical and iinflatmory.
• Hypoxia is a common thing and occurs w/ Decreased oxygen. LOSS of hemoglobn.
• Decreased numbers, respitory and cardivasicuar and, and losss cyctochomes.
• Cyanide causes cell hyspoxa blocking the axidatioce in micochondrla prventing metbliosim Pesticade cause block enzyme and prevents proper nerve pulses
• Infetious- causes direct action or toxin production.

immunologic (Hypersensitivity)

• A protective responds from the body that can be brought from a bacterial infection. -Swelling from this also leads to pothsseium (K) from cells and water flow

Addition Factors

-Grenteic. Nutritaional, and pyshsial agent

• --. Chronomosical diodates
• abnoral gene development

Nutrional:

Good nutriton for cell to fight off diseases. Ex obesity. malnutiton and vitamn access

• -- physical:heat :burn .Colf/ frost Redion- sickness and tumours.